System and method for monitoring control points during reactive motion

ABSTRACT

A system and method of monitoring control points during reactive motion includes a computer-assisted device. The computer-assisted device includes the one or more articulated arms and a control unit coupled to the one or more articulated arms. The control unit is configured to perform operations comprising determining, before movement of a table separate from the computer-assisted device, a latched spatial configuration of a plurality of control points associated with the one or more articulated arms; determining one or more geometric attributes of the latched spatial configuration; determining an actual spatial configuration of the plurality of control points as the one or more articulated arms track the movement of the table; determining a difference between the one or more geometric attributes of the latched spatial configuration and corresponding one or more geometric attributes of the actual spatial configuration; and performing, based on the determined difference, a remedial action.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/522,155, entitled “System and Method for Monitoring Control PointsDuring Reactive Motion,” which was filed on Apr. 26, 2017, which is aU.S. National Stage patent application of International PatentApplication No. PCT/US2015/057670, entitled “System and Method forMonitoring Control Points During Reactive Motion,” which was filed onOct. 27, 2015, the benefit of which is claimed, and claims priority toU.S. Provisional Patent Application No. 62/134,252 entitled “System andMethod for Monitoring Control Points During Reactive Motion,” which wasfiled on Mar. 17, 2015 and U.S. Provisional Patent Application No.62/069,245 entitled “System and Method for Integrated Operating Table,”which was filed Oct. 27, 2014, each of which are hereby incorporated byreference in their entirety.

TECHNICAL FIELD

The present disclosure relates generally to operation of devices witharticulated arms and more particularly to monitoring control pointsduring reactive motion.

BACKGROUND

More and more devices are being replaced with autonomous andsemiautonomous electronic devices. This is especially true in thehospitals of today with large arrays of autonomous and semiautonomouselectronic devices being found in operating rooms, interventionalsuites, intensive care wards, emergency rooms, and the like. Forexample, glass and mercury thermometers are being replaced withelectronic thermometers, intravenous drip lines now include electronicmonitors and flow regulators, and traditional hand-held surgicalinstruments are being replaced by computer-assisted medical devices.

These electronic devices provide both advantages and challenges to thepersonnel operating them. Many of these electronic devices may becapable of autonomous or semiautonomous motion of one or morearticulated arms and/or end effectors. These one or more articulatedarms and/or end effectors each include a combination of links andarticulated joints that support motion of the articulated arms and/orend effectors. In many cases, the articulated joints are manipulated toobtain a desired position and/or orientation (collectively, a desiredpose) of a corresponding instrument located at a distal end of the linksand articulated joints of a corresponding articulated arm. Each of thearticulated joints proximal to the instrument provides the correspondingarticulated arm with at least one degree of freedom that may be used tomanipulate the position and/or orientation of the correspondinginstrument. In many cases, the corresponding articulated arms mayinclude at least six degrees of freedom that allow for controlling a x,y, and z position of the corresponding instrument as well as a roll,pitch, and yaw orientation of the corresponding instrument. Eacharticulated arm may further provide a remote center of motion. In somecases, one or more articulated arms and corresponding remote centers ofmotion or other points on the articulated arms may be allowed to move inorder to track the movement of other parts of the electronic device. Forexample, when an instrument is inserted into a body opening, such as anincision site or body orifice, on a patient during a surgical procedureand a surgical table on which the patient is placed is undergoingmotion, it is important for the articulated arm to be able to adjust theposition of the instrument to the changes in the positions of the bodyopening. Depending upon the design and/or implementation of thearticulated arm, the body opening on the patient may correspond to theremote center of motion for the articulated arm.

As each of the one or more articulated arms track the underlyingmovement, the corresponding articulated arm and/or other parts of theelectronic device attempt to compensate for the movement in the bodyopening. When the articulated arms are not able to fully compensate forthe movement of the body opening points, this may result in undesirableand/or unsafe consequences. This lack of compliance with the movement ofthe incision point may result in injury to the patient, damage to thearticulated arms, and/or other undesirable outcomes.

Accordingly, it would be desirable to monitor the ability of thearticulated arms to compensate for underlying movement in controlpoints, such as body openings.

SUMMARY

Consistent with some embodiments, a computer-assisted medical deviceincludes one or more articulated arms each having a control point and acontrol unit coupled to the one or more articulated arms. The one ormore articulated arms and corresponding control points are configured totrack movement of a surgical table. The control unit monitors a spatialconfiguration of the one or more control points by determining anexpected spatial configuration of the one or more control points duringthe movement of the surgical table, determining an actual spatialconfiguration of the one or more control points during the movement ofthe surgical table, and determining a difference between the expectedspatial configuration and the actual spatial configuration.

Consistent with some embodiments, a method of monitoring a spatialconfiguration of one or more control points of a computer-assistedmedical device includes determining an expected spatial configuration ofthe one or more control points during movement of a surgical table,determining an actual spatial configuration of the one or more controlpoints during the movement of the surgical table, and determining adifference between the expected spatial configuration and the actualspatial configuration. The one or more control points correspond to oneor more articulated arms and are configured to track the movement of thesurgical table.

Consistent with some embodiments, a non-transitory machine-readablemedium includes a plurality of machine-readable instructions which whenexecuted by one or more processors associated with a medical device areadapted to cause the one or more processors to perform a method. Themethod includes determining an expected spatial configuration of one ormore control points during movement of a surgical table, determining anactual spatial configuration of the one or more control points in duringthe movement of the surgical table, and determining a difference betweenthe expected spatial configuration and the actual spatial configuration.The one or more control points correspond to one or more articulatedarms and are configured to track the movement of the surgical table.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified diagram of a computer-assisted system accordingto some embodiments.

FIG. 2 is a simplified diagram showing a computer-assisted systemaccording to some embodiments.

FIG. 3 is a simplified diagram of a kinematic model of acomputer-assisted medical system according to some embodiments.

FIG. 4 is a simplified diagram of the method of monitoring one or morecontrol points during table movement according to some embodiments.

FIG. 5 is a simplified diagram of a control point position during tablemovement in a height-only mode according to some embodiments.

FIG. 6 is a simplified diagram of a control point constellation duringrotational table movement according to some embodiments.

FIGS. 7A-7G are simplified schematic views that illustrate variouscomputer-assisted device system architectures that incorporate theintegrated computer-assisted device and movable surgical table featuresdescribed herein.

In the figures, elements having the same designations have the same orsimilar functions.

DETAILED DESCRIPTION

In the following description, specific details are set forth describingsome embodiments consistent with the present disclosure. It will beapparent to one skilled in the art, however, that some embodiments maybe practiced without some or all of these specific details. The specificembodiments disclosed herein are meant to be illustrative but notlimiting. One skilled in the art may realize other elements that,although not specifically described here, are within the scope and thespirit of this disclosure. In addition, to avoid unnecessary repetition,one or more features shown and described in association with oneembodiment may be incorporated into other embodiments unlessspecifically described otherwise or if the one or more features wouldmake an embodiment non-functional. The term “including” means includingbut not limited to, and each of the one or more individual itemsincluded should be considered optional unless otherwise stated.Similarly, the term “may” indicates that an item is optional.

FIG. 1 is a simplified diagram of a computer-assisted system 100according to some embodiments. As shown in FIG. 1, computer-assistedsystem 100 includes a device 110 with one or more movable or articulatedarms 120. Each of the one or more articulated arms 120 supports one ormore end effectors. In some examples, device 110 may be consistent witha computer-assisted surgical device. The one or more articulated arms120 each provides support for one or more instruments, surgicalinstruments, imaging devices, and/or the like mounted to a distal end ofat least one of the articulated arms 120. Device 110 may further becoupled to an operator workstation (not shown), which may include one ormore master controls for operating the device 110, the one or morearticulated arms 120, and/or the end effectors. In some embodiments,device 110 and the operator workstation may correspond to a da Vinci®Surgical System commercialized by Intuitive Surgical, Inc. of Sunnyvale,Calif. In some embodiments, computer-assisted surgical devices withother configurations, fewer or more articulated arms, and/or the likemay optionally be used with computer-assisted system 100.

Device 110 is coupled to a control unit 130 via an interface. Theinterface may include one or more wireless links, cables, connectors,and/or buses and may further include one or more networks with one ormore network switching and/or routing devices. Control unit 130 includesa processor 140 coupled to memory 150. Operation of control unit 130 iscontrolled by processor 140. And although control unit 130 is shown withonly one processor 140, it is understood that processor 140 may berepresentative of one or more central processing units, multi-coreprocessors, microprocessors, microcontrollers, digital signalprocessors, field programmable gate arrays (FPGAs), application specificintegrated circuits (ASICs), and/or the like in control unit 130.Control unit 130 may be implemented as a stand-alone subsystem and/orboard added to a computing device or as a virtual machine. In someembodiments, control unit may be included as part of the operatorworkstation and/or operated separately from, but in coordination withthe operator workstation.

Memory 150 is used to store software executed by control unit 130 and/orone or more data structures used during operation of control unit 130.Memory 150 may include one or more types of machine readable media. Somecommon forms of machine readable media may include floppy disk, flexibledisk, hard disk, magnetic tape, any other magnetic medium, CD-ROM, anyother optical medium, punch cards, paper tape, any other physical mediumwith patterns of holes, RAM, PROM, EPROM, FLASH-EPROM, any other memorychip or cartridge, and/or any other medium from which a processor orcomputer is adapted to read.

As shown, memory 150 includes a motion control application 160 thatsupports autonomous and/or semiautonomous control of device 110. Motioncontrol application 160 may include one or more application programminginterfaces (APIs) for receiving position, motion, and/or other sensorinformation from device 110, exchanging position, motion, and/orcollision avoidance information with other control units regarding otherdevices, such as a surgical table and/or imaging device, and/or planningand/or assisting in the planning of motion for device 110, articulatedarms 120, and/or the end effectors of device 110. And although motioncontrol application 160 is depicted as a software application, motioncontrol application 160 may be implemented using hardware, software,and/or a combination of hardware and software.

In some embodiments, computer-assisted system 100 may be found in anoperating room and/or an interventional suite. And althoughcomputer-assisted system 100 includes only one device 110 with twoarticulated arms 120, one of ordinary skill would understand thatcomputer-assisted system 100 may include any number of devices witharticulated arms and/or end effectors of similar and/or different designfrom device 110. In some examples, each of the devices may include feweror more articulated arms and/or end effectors.

Computer-assisted system 100 further includes a surgical table 170. Likethe one or more articulated arms 120, surgical table 170 supportsarticulated movement of a table top 180 relative to a base of surgicaltable 170. In some examples, the articulated movement of table top 180may include support for changing a height, a tilt, a slide, aTrendelenburg orientation, and/or the like of table top 180. Althoughnot shown, surgical table 170 may include one or more control inputs,such as a surgical table command unit for controlling the positionand/or orientation of table top 180. In some embodiments, surgical table170 may correspond to one or more of the surgical tables commercializedby Trumpf Medical Systems GmbH of Germany.

Surgical table 170 is also coupled to control unit 130 via acorresponding interface. The interface may include one or more wirelesslinks, cables, connectors, and/or buses and may further include one ormore networks with one or more network switching and/or routing devices.In some embodiments, surgical table 170 may be coupled to a differentcontrol unit than control unit 130. In some examples, motion controlapplication 160 may include one or more application programminginterfaces (APIs) for receiving position, motion, and/or other sensorinformation associated with surgical table 170 and/or table top 180. Insome examples, motion control application 160 may plan and/or assist inthe planning of motion for surgical table 170 and/or table top 180. Insome examples, motion control application 160 may contribute to motionplans associated with collision avoidance, adapting to and/or avoidrange of motion limits in joints and links, movement of articulatedarms, instruments, end effectors, surgical table components, and/or thelike to compensate for other motion in the articulated arms,instruments, end effectors, surgical table components, and/or the like,adjust a viewing device such as an endoscope to maintain and/or place anarea of interest and/or one or more instruments or end effectors withina field of view of the viewing device. In some examples, motion controlapplication 160 may prevent motion of surgical table 170 and/or tabletop 180, such as by preventing movement of surgical table 170 and/ortable top 180 through use of the surgical table command unit. In someexamples, motion control application 160 may help register device 110with surgical table 170 so that a geometric relationship between device110 and surgical table 170 is known. In some examples, the geometricrelationship may include a translation and/or one or more rotationsbetween coordinate frames maintained for device 110 and surgical table170.

FIG. 2 is a simplified diagram showing a computer-assisted system 200according to some embodiments. For example, the computer-assisted system200 may be consistent with computer-assisted system 100. As shown inFIG. 2, the computer-assisted system 200 includes a computer-assisteddevice 210 with one or more articulated arms and a surgical table 280.Although not shown in FIG. 2, the computer-assisted device 210 and thesurgical table 280 are coupled together using one or more interfaces andone or more control units so that at least kinematic information aboutthe surgical table 280 is known to the motion control application beingused to perform motion of the articulated arms of the computer-assisteddevice 210.

The computer-assisted device 210 includes various links and joints. Inthe embodiments of FIG. 2, the computer-assisted device is generallydivided into three different sets of links and joints. Starting at theproximal end with a mobile cart 215 or patient-side cart 215 is a set-upstructure 220. Coupled to a distal end of the set-up structure is aseries of links and set-up joints 240 forming an articulated arm. Andcoupled to a distal end of the set-up joints 240 is a multi jointedmanipulator 260. In some examples, the series of set-up joints 240 andmanipulator 260 may correspond to one of the articulated arms 120. Andalthough the computer-assisted device is shown with only one series ofset-up joints 240 and a corresponding manipulator 260, one of ordinaryskill would understand that the computer-assisted device may includemore than one series of set-up joints 240 and corresponding manipulators260 so that the computer-assisted device is equipped with multiplearticulated arms.

As shown, the computer-assisted device 210 is mounted on the mobile cart215. The mobile cart 215 enables the computer-assisted device 210 to betransported from location to location, such as between operating roomsor within an operating room to better position the computer-assisteddevice in proximity to the surgical table 280. The set-up structure 220is mounted on the mobile cart 215. As shown in FIG. 2, the set-upstructure 220 includes a two part column including column links 221 and222. Coupled to the upper or distal end of the column link 222 is ashoulder joint 223. Coupled to the shoulder joint 223 is a two-part boomincluding boom links 224 and 225. At the distal end of the boom link 225is a wrist joint 226, and coupled to the wrist joint 226 is an armmounting platform 227.

The links and joints of the set-up structure 220 include various degreesof freedom for changing the position and orientation (i.e., the pose) ofthe arm mounting platform 227. For example, the two-part column is usedto adjust a height of the arm mounting platform 227 by moving theshoulder joint 223 up and down along an axis 232. The arm mountingplatform 227 is additionally rotated about the mobile cart 215, thetwo-part column, and the axis 232 using the shoulder joint 223. Thehorizontal position of the arm mounting platform 227 is adjusted alongan axis 234 using the two-part boom. And the orientation of the armmounting platform 227 may also adjusted by rotation about an armmounting platform orientation axis 236 using the wrist joint 226. Thus,subject to the motion limits of the links and joints in the set-upstructure 220, the position of the arm mounting platform 227 may beadjusted vertically above the mobile cart 215 using the two-part column.The positions of the arm mounting platform 227 may also be adjustedradially and angularly about the mobile cart 215 using the two-part boomand the shoulder joint 223, respectively. And the angular orientation ofthe arm mounting platform 227 may also be changed using the wrist joint226.

The arm mounting platform 227 is used as a mounting point for one ormore articulated arms. The ability to adjust the height, horizontalposition, and orientation of the arm mounting platform 227 about themobile cart 215 provides a flexible set-up structure for positioning andorienting the one or more articulated arms about a work space locatednear the mobile cart 215 where an operation or procedure is to takeplace. For example, arm mounting platform 227 may be positioned above apatient so that the various articulated arms and their correspondingmanipulators and instruments have sufficient range of motion to performa surgical procedure on the patient. FIG. 2 shows a single articulatedarm coupled to the arm mounting platform 227 using a first set-up joint242. And although only one articulated arm is shown, one of ordinaryskill would understand that multiple articulated arms may be coupled tothe arm mounting platform 227 using additional first set-up joints.

The first set-up joint 242 forms the most proximal portion of the set-upjoints 240 section of the articulated arm. The set-up joints 240 mayfurther include a series of joints and links. As shown in FIG. 2, theset-up joints 240 include at least links 244 and 246 coupled via one ormore joints (not expressly shown). The joints and links of the set-upjoints 240 include the ability to rotate the set-up joints 240 relativeto the arm mounting platform 227 about an axis 252 using the firstset-up joint 242, adjust a radial or horizontal distance between thefirst set-up joint 242 and the link 246, adjust a height of amanipulator mount 262 at the distal end of link 246 relative to the armmounting platform 227 along an axis 254, and rotate the manipulatormount 262 about axis 254. In some examples, the set-up joints 240 mayfurther include additional joints, links, and axes permitting additionaldegrees of freedom for altering a pose of the manipulator mount 262relative to the arm mounting platform 227.

The manipulator 260 is coupled to the distal end of the set-up joints240 via the manipulator mount 262. The manipulator 260 includesadditional joints 264 and links 266 with an instrument carriage 268mounted at the distal end of the manipulator 260. An instrument 270 ismounted to the instrument carriage 268. Instrument 270 includes a shaft272, which is aligned along an insertion axis. The shaft 272 istypically aligned so that it passes through a remote center of motion274 associated with the manipulator 260. Location of the remote centerof motion 274 is typically maintained in a fixed translationalrelationship relative to the manipulator mount 262 so that operation ofthe joints 264 in the manipulator 260 result in rotations of the shaft272 about the remote center of motion 274. Depending upon theembodiment, the fixed translational relationship of the remote center ofmotion 274 relative to the manipulator mount 262 is maintained usingphysical constraints in the joints 264 and links 266 of the manipulator260, using software constraints placed on the motions permitted for thejoints 264, and/or a combination of both. Representative embodiments ofcomputer-assisted surgical devices using remote centers of motionmaintained using physical constraints in joints and links are describedin U.S. patent application Ser. No. 13/906,888 entitled “Redundant Axisand Degree of Freedom for Hardware-Constrained Remote Center RoboticManipulator,” which was filed May 13, 2013, and representativeembodiments of computer-assisted surgical devices using remote centersof motion maintained by software constraints are described in U.S. Pat.No. 8,004,229 entitled “Software Center and Highly Configurable RoboticSystems for Surgery and Other Uses,” which was filed May 19, 2005, thespecifications of which are hereby incorporated by reference in theirentirety In some examples, the remote center of motion 274 maycorrespond to a location of a body opening, such as an incision site orbody orifice, in a patient 278 where shaft 272 is inserted into thepatient 278. Because the remote center of motion 274 corresponds to thebody opening, as the instrument 270 is used, the remote center of motion274 remains stationary relative to the patient 278 to limit stresses onthe anatomy of the patient 278 at the remote center of motion 274. Insome examples, the shaft 272 may be optionally passed through a cannula(not shown) located at the body opening. In some examples, instrumentshaving a relatively larger shaft or guide tube outer diameter (e.g., 4-5mm or more) may be passed through the body opening using a cannula andthe cannula may optionally be omitted for instruments having arelatively smaller shaft or guide tube outer diameter (e.g., 2-3 mm orless).

At the distal end of the shaft 272 is an end effector 276. The degreesof freedom in the manipulator 260 due to the joints 264 and the links266 may permit at least control of the roll, pitch, and yaw of the shaft272 and/or the end effector 276 relative to the manipulator mount 262.In some examples, the degrees of freedom in the manipulator 260 mayfurther include the ability to advance and/or withdraw the shaft 272using the instrument carriage 268 so that the end effector 276 may beadvanced and/or withdrawn along the insertion axis and relative to theremote center of motion 274. In some examples, the manipulator 260 maybe consistent with manipulators for use with the da Vinci® SurgicalSystem commercialized by Intuitive Surgical, Inc. of Sunnyvale, Calif.In some examples, the instrument 270 may be an imaging device such as anendoscope, a gripper, a surgical instrument such as a cautery or ascalpel, and/or the like. In some examples, the end effector 276 mayinclude additional degrees of freedom, such as roll, pitch, yaw, grip,and/or the like that allow for additional localized manipulation ofportions of the end effector 276 relative to the distal end of the shaft272.

During a surgery or other medical procedure, the patient 278 istypically located on the surgical table 280. The surgical table 280includes a table base 282 and a table top 284, with the table base 282being located in proximity to mobile cart 215 so that the instrument 270and/or end effector 276 may be manipulated by the computer-assisteddevice 210 while the shaft 272 of instrument 270 is inserted into thepatient 278 at the body opening. The surgical table 280 further includesan articulated structure 290 that includes one or more joints or linksbetween the table base 282 and the table top 284 so that the relativelocation of the table top 284, and thus the patient 278, relative to thetable base 282 is controlled. In some examples, the articulatedstructure 290 may be configured so that the table top 284 is controlledrelative to a virtually-defined table motion isocenter 286 that may belocated at a point above the table top 284. In some examples, isocenter286 may be located within the interior of the patient 278. In someexamples, isocenter 286 may be collocated with the body wall of thepatient at or near one of the body openings, such as a body opening sitecorresponding to remote center of motion 274.

As shown in FIG. 2, the articulated structure 290 includes a heightadjustment joint 292 so that the table top 284 may be raised and/orlowered relative to the table base 282. The articulated structure 290further includes joints and links to change both the tilt 294 andTrendelenburg 296 orientation of the table top 284 relative to theisocenter 286. The tilt 294 allows the table top 284 to be tiltedside-to-side so that either the right or left side of the patient 278 isrotated upward relative to the other side of the patient 278 (i.e.,about a longitudinal or head-to-toe (cranial-caudal) axis of the tabletop 284). The Trendelenburg 296 allows the table top 284 to be rotatedso that either the feet of the patient 278 are raised (Trendelenburg) orthe head of the patient 278 is raised (reverse Trendelenburg). In someexamples, either the tilt 294 and/or the Trendelenburg 296 rotations maybe adjusted to generate rotations about isocenter 286. The articulatedstructure 290 further includes additional links and joints 298 to slidethe table top 284 along the longitudinal (cranial-caudal) axis relativeto the table base 282 with generally a left and/or right motion asdepicted in FIG. 2.

FIGS. 7A-7G are simplified schematic views that illustrate variouscomputer-assisted device system architectures that incorporate theintegrated computer-assisted device and movable surgical table featuresdescribed herein. The various illustrated system components are inaccordance with the principles described herein. In these illustrations,the components are simplified for clarity, and various details such asindividual links, joints, manipulators, instruments, end effectors, etc.are not shown, but they should be understood to be incorporated in thevarious illustrated components.

In these architectures, cannulas associated with one or more surgicalinstruments or clusters of instruments are not shown, and it should beunderstood that cannulas and other instrument guide devices optionallymay be used for instruments or instrument clusters having a relativelylarger shaft or guide tube outer diameter (e.g., 4-5 mm or more) andoptionally may be omitted for instruments having a relatively smallershaft or guide tube outer diameter (e.g., 2-3 mm or less).

Also in these architectures, teleoperated manipulators should beunderstood to include manipulators that during surgery define a remotecenter of motion by using hardware constraints (e.g., fixed intersectinginstrument pitch, yaw, and roll axes) or software constraints (e.g.,software-constrained intersecting instrument pitch, yaw, and roll axes).A hybrid of such instrument axes of rotation may be defined (e.g.,hardware-constrained roll axis and software-constrained pitch and yawaxes) are also possible. Further, some manipulators may not define andconstrain any surgical instrument axes of rotation during a procedure,and some manipulators may define and constrain only one or twoinstrument axes of rotation during a procedure.

FIG. 7A illustrates a movable surgical table 1100 and asingle-instrument computer-assisted device 1101 a are shown. Surgicaltable 1100 includes a movable table top 1102 and a table supportstructure 1103 that extends from a mechanically grounded table base 1104to support the table top 1102 at a distal end. In some examples,surgical table 1100 may be consistent with surgical table 170 and/or280. Computer-assisted device 1101 a includes a teleoperated manipulatorand a single instrument assembly 1105 a. Computer-assisted device 1101 aalso includes a support structure 1106 a that is mechanically groundedat a proximal base 1107 a and that extends to support manipulator andinstrument assembly 1105 a at a distal end. Support structure 1106 a isconfigured to allow assembly 1105 a to be moved and held in variousfixed poses with reference to surgical table 1100. Base 1107 a isoptionally permanently fixed or movable with reference to surgical table1100. Surgical table 1100 and computer-assisted device 1101 a operatetogether as described herein.

FIG. 7A further shows an optional second computer-assisted device 1101b, which illustrates that two, three, four, five, or more individualcomputer-assisted devices may be included, each having a correspondingindividual teleoperated manipulator and single-instrument assembly(ies)1105 b supported by a corresponding support structure 1106 b.Computer-assisted device 1101 b is mechanically grounded, and assemblies1105 b are posed, similarly to computer-assisted device 1101 a. Surgicaltable 1100 and computer-assisted devices 1101 a and 1101 b together makea multi-instrument surgical system, and they operate together asdescribed herein. In some examples, computer-assisted devices 1101 aand/or 1101 b may be consistent with computer-assisted devices 110and/or 210.

As shown in FIG. 7B, another movable surgical table 1100 and acomputer-assisted device 1111 are shown. Computer-assisted device 1111is a multi-instrument device that includes two, three, four, five, ormore individual teleoperated manipulator and single-instrumentassemblies as shown by representative manipulator and instrumentassemblies 1105 a and 1105 b. The assemblies 1105 a and 1105 b ofcomputer-assisted device 1111 are supported by a combined supportstructure 1112, which allows assemblies 1105 a and 1105 b to be movedand posed together as a group with reference to surgical table 1100. Theassemblies 1105 a and 1105 b of computer-assisted device 1111 are alsoeach supported by a corresponding individual support structure 1113 aand 1113 b, respectively, which allows each assembly 1105 a and 1105 bto be individually moved and posed with reference to surgical table 1100and to the one or more other assemblies 1105 a and 1105 b. Examples ofsuch a multi-instrument surgical system architecture are the da VinciSi® Surgical System and the da Vinci® Xi™ Surgical System,commercialized by Intuitive Surgical, Inc. Surgical table 1100 and asurgical manipulator system comprising an example computer-assisteddevice 1111 operate together as described herein. In some examples,computer-assisted device 1111 is consistent with computer-assisteddevices 110 and/or 210.

The computer-assisted devices of FIGS. 7A and 7B are each shownmechanically grounded at the floor. But, one or more suchcomputer-assisted devices may optionally be mechanically grounded at awall or ceiling and be permanently fixed or movable with reference tosuch a wall or ceiling ground. In some examples, computer-assisteddevices may be mounted to the wall or ceiling using a track or gridsystem that allows the support base of the computer-assisted systems tobe moved relative to the surgical table. In some examples, one or morefixed or releasable mounting clamps may be used to mount the respectivesupport bases to the track or grid system. As shown in FIG. 7C, acomputer-assisted device 1121 a is mechanically grounded at a wall, anda computer-assisted device 1121 b is mechanically grounded at a ceiling.

In addition, computer-assisted devices may be indirectly mechanicallygrounded via the movable surgical table 1100. As shown in FIG. 7D, acomputer-assisted device 1131 a is coupled to the table top 1102 ofsurgical table 1100. Computer-assisted device 1131 a may optionally becoupled to other portions of surgical table 1100, such as table supportstructure 1103 or table base 1104, as indicated by the dashed structuresshown in FIG. 7D. When table top 1102 moves with reference to tablesupport structure 1103 or table base 1104, the computer-assisted device1131 a likewise moves with reference to table support structure 1103 ortable base 1104. When computer-assisted device 1131 a is coupled totable support structure 1103 or table base 1104, however, the base ofcomputer-assisted device 1131 a remains fixed with reference to groundas table top 1102 moves. As table motion occurs, the body opening whereinstruments are inserted into the patient may move as well because thepatient's body may move and change the body opening locations relativeto the table top 1102. Therefore, for embodiments in whichcomputer-assisted device 1131 a is coupled to the table top 1102, thetable top 1102 functions as a local mechanical ground, and the bodyopenings move with reference to the table top 1102, and so withreference to the computer-assisted device 1131 a as well. FIG. 7D alsoshows that a second computer-assisted device 1131 b optionally may beadded, configured similarly to computer-assisted device 1131 a to createa multi-instrument system. Systems that include one or morecomputer-assisted device coupled to the surgical table operate asdisclosed herein.

In some embodiments, other combinations of computer-assisted deviceswith the same or hybrid mechanical groundings are possible. For example,a system may include one computer-assisted device mechanically groundedat the floor, and a second computer-assisted device mechanicallygrounded to the floor via the surgical table. Such hybrid mechanicalground systems operate as disclosed herein.

Inventive aspects also include single-body opening systems in which twoor more surgical instruments enter the body via a single body opening.Examples of such systems are shown in U.S. Pat. No. 8,852,208 entitled“Surgical System Instrument Mounting,” which was filed Aug. 12, 2010,and U.S. Pat. No. 9,060,678 entitled “Minimally Invasive SurgicalSystem,” which was filed Jun. 13, 2007, both of which are incorporatedby reference. FIG. 7E illustrates a teleoperated multi-instrumentcomputer-assisted device 1141 together with surgical table 1100 asdescribed above. Two or more instruments 1142 are each coupled to acorresponding manipulator 1143, and the cluster of instruments 1142 andinstrument manipulators 1143 are moved together by a system manipulator1144. The system manipulator 1144 is supported by a support assembly1145 that allows system manipulator 1144 to be moved to and fixed atvarious poses. Support assembly 1145 is mechanically grounded at a base1146 consistent with the descriptions above. The two or more instruments1142 are inserted into the patient at the single body opening.Optionally, the instruments 1142 extend together through a single guidetube, and the guide tube optionally extends through a cannula, asdescribed in the references cited above. Computer-assisted device 1141and surgical table 1100 operate together as described herein.

FIG. 7F illustrates another multi-instrument, single-body openingcomputer-assisted device 1151 mechanically grounded via the surgicaltable 1100, optionally by being coupled to table top 1102, table supportstructure 1103, or table base 1104. The descriptions above withreference to FIG. 7D also applies to the mechanical grounding optionsillustrated in FIG. 7F. Computer-assisted device 1151 and surgical table1100 work together as described herein.

FIG. 7G illustrates that one or more teleoperated multi-instrument,single-body opening computer-assisted devices 1161 and one or moreteleoperated single-instrument computer-assisted devices 1162 may becombined to operate with surgical table 1100 as described herein. Eachof the computer-assisted devices 1161 and 1162 may be mechanicallygrounded, directly or via another structure, in various ways asdescribed above.

FIG. 3 is a simplified diagram of a kinematic model 300 of acomputer-assisted medical system according to some embodiments. As shownin FIG. 3, kinematic model 300 may include kinematic informationassociated with many sources and/or devices. The kinematic informationis based on known kinematic models for the links and joints of acomputer-assisted medical device and a surgical table. The kinematicinformation is further based on information associated with the positionand/or orientation of the joints of the computer-assisted medical deviceand the surgical table. In some examples, the information associatedwith the position and/or orientation of the joints may be derived fromone or more sensors, such as encoders, measuring the linear positions ofprismatic joints and the rotational positions of revolute joints.

The kinematic model 300 includes several coordinate frames or coordinatesystems and transformations, such as homogeneous transforms, fortransforming positions and/or orientation from one of the coordinateframes to another of the coordinate frames. In some examples, thekinematic model 300 may be used to permit the forward and/or reversemapping of positions and/or orientations in one of the coordinate framesin any other of the coordinate frames by composing the forward and/orreverse/inverse transforms noted by the transform linkages included inFIG. 3. In some examples, when the transforms are modeled as homogenoustransforms in matrix form, the composing is accomplished using matrixmultiplication. In some embodiments, the kinematic model 300 may be usedto model the kinematic relationships of the computer-assisted device 210and the surgical table 280 of FIG. 2.

The kinematic model 300 includes a table base coordinate frame 305 thatis used to model a position and/or orientation of a surgical table, suchas surgical table 170 and/or surgical table 280. In some examples, thetable base coordinate frame 305 may be used to model other points on thesurgical table relative to a reference point and/or orientationassociated with the surgical table. In some examples, the referencepoint and/or orientation may be associated with a table base of thesurgical table, such as the table base 282. In some examples, the tablebase coordinate frame 305 may be suitable for use as a world coordinateframe for the computer-assisted system.

The kinematic model 300 further includes a table top coordinate frame310 that may be used to model positions and/or orientations in acoordinate frame representative of a table top of the surgical table,such as the table top 284. In some examples, the table top coordinateframe 310 may be centered about a rotational center or isocenter of thetable top, such as isocenter 286. In some examples, the z-axis of thetable top coordinate frame 310 may be oriented vertically with respectto a floor or surface on which the surgical table is placed and/ororthogonal to the surface of the table top. In some examples, the x- andy-axes of the table top coordinate frame 310 may be oriented to capturethe longitudinal (head to toe) and lateral (side-to-side) major axes ofthe table top. In some examples, a table base to table top coordinatetransform 315 is used to map positions and/or orientations between thetable top coordinate frame 310 and the table base coordinate frame 305.In some examples, one or more kinematic models of an articulatedstructure of the surgical table, such as articulated structure 290,along with past and/or current joint sensor readings is used todetermine the table base to table top coordinate transform 315. In someexamples consistent with the embodiments of FIG. 2, the table base totable top coordinate transform 315 models the composite effect of theheight, tilt, Trendelenburg, and/or slide settings associated with thesurgical table.

The kinematic model 300 further includes a device base coordinate framethat is used to model a position and/or orientation of acomputer-assisted device, such as computer-assisted device 110 and/orcomputer-assisted device 210. In some examples, the device basecoordinate frame 320 may be used to model other points on thecomputer-assisted device relative to a reference point and/ororientation associated with the computer-assisted device. In someexamples, the reference point and/or orientation may be associated witha device base of the computer-assisted device, such as the mobile cart215. In some examples, the device base coordinate frame 320 may besuitable for use as the world coordinate frame for the computer-assistedsystem.

In order to track positional and/or orientational relationships betweenthe surgical table and the computer-assisted device, it is oftendesirable to perform a registration between the surgical table and thecomputer-assisted device. As shown in FIG. 3, the registration may beused to determine a registration transform 325 between the table topcoordinate frame 310 and the device base coordinate from 320. In someembodiments, the registration transform 325 may be a partial or fulltransform between the table top coordinate frame 310 and the device basecoordinate frame 320. The registration transform 325 is determined basedon the architectural arrangements between the surgical table and thecomputer-assisted device.

In the examples of FIGS. 7D and 7F, where the computer-assisted deviceis mounted to the table top 1102, the registration transform 325 isdetermined from the table base to table top coordinate transform 315 andknowing where the computer-assisted device is mounted to the table top112.

In the examples of FIGS. 7A-7C, 7E, and 7F, where the computer-assisteddevice is placed on the floor or mounted to the wall or ceiling,determination of the registration transform 325 is simplified by placingsome restrictions on the device base coordinate frame 320 and the tablebase coordinate frame 305. In some examples, these restrictions includethat both the device base coordinate frame 320 and the table basecoordinate frame 305 agree on the same vertical up or z-axis. Under theassumption that the surgical table is located on a level floor, therelative orientations of the walls of the room (e.g., perpendicular tothe floor) and the ceiling (e.g., parallel to the floor) are known it ispossible for a common vertical up or z axis (or a suitable orientationtransform) to be maintained for both the device base coordinate frame320 and the table base coordinate frame 305 or a suitable orientationtransform. In some examples, because of the common z-axis, theregistration transform 325 may optionally model just the rotationalrelationship of the device base to the table base about the z-axis ofthe table base coordinate frame 305 (e.g., a θz registration). In someexamples, the registration transform 325 may optionally also model ahorizontal offset between the table base coordinate frame 305 and thedevice base coordinate frame 320 (e.g., a XY registration). This ispossible because the vertical (z) relationship between thecomputer-assisted device and the surgical table are known. Thus, changesin a height of the table top in the table base to table top transform315 are analogous to vertical adjustments in the device base coordinateframe 320 because the vertical axes in the table base coordinate frame305 and the device base coordinate frame 320 are the same or nearly thesame so that changes in height between the table base coordinate frame305 and the device base coordinate frame 320 are within a reasonabletolerance of each other. In some examples, the tilt and Trendelenburgadjustments in the table base to table top transform 315 may be mappedto the device base coordinate frame 320 by knowing the height of thetable top (or its isocenter) and the θz and/or XY registration. In someexamples, the registration transform 325 and the table base to table toptransform 315 may be used to model the computer-assisted surgical deviceas if it were attached to the table top even when this isarchitecturally not the case.

The kinematic model 300 further includes an arm mounting platformcoordinate frame 330 that is used as a suitable model for a sharedcoordinate frame associated with the most proximal points on thearticulated arms of the computer-assisted device. In some embodiments,the arm mounting platform coordinate frame 330 may be associated withand oriented relative to a convenient point on an arm mounting platform,such as the arm mounting platform 227. In some examples, the centerpoint of the arm mounting platform coordinate frame 330 may be locatedon the arm mounting platform orientation axis 236 with the z-axis of thearm mounting platform coordinate frame 330 being aligned with armmounting platform orientation axis 236. In some examples, a device baseto arm mounting platform coordinate transform 335 is used to mappositions and/or orientations between the device base coordinate frame320 and the arm mounting platform coordinate frame 330. In someexamples, one or more kinematic models of the links and joints of thecomputer-assisted device between the device base and the arm mountingplatform, such as the set-up structure 220, along with past and/orcurrent joint sensor readings are used to determine the device base toarm mounting platform coordinate transform 335. In some examplesconsistent with the embodiments of FIG. 2, the device base to armmounting platform coordinate transform 335 may model the compositeeffect of the two-part column, shoulder joint, two-part boom, and wristjoint of the setup structure portion of the computer-assisted device.

The kinematic model 300 further includes a series of coordinate framesand transforms associated with each of the articulated arms of thecomputer-assisted device. As shown in FIG. 3, the kinematic model 300includes coordinate frames and transforms for three articulated arms,although one of ordinary skill would understand that differentcomputer-assisted devices may include fewer and/or more articulated arms(e.g., one, two, four, five, or more). Consistent with the configurationof the links and joints of the computer-assisted device 210 of FIG. 2,each of the articulated arms is modeled using a manipulator mountcoordinate frame, a remote center of motion coordinate frame, and aninstrument or camera coordinate frame, depending on a type of instrumentmounted to the distal end of the articulated arm.

In the kinematic model 300, the kinematic relationships of a first oneof the articulated arms is captured using a manipulator mount coordinateframe 341, a remote center of motion coordinate frame 342, an instrumentcoordinate frame 343, an arm mounting platform to manipulator mounttransform 344, a manipulator mount to remote center of motion transform345, and a remote center of motion to instrument transform 346. Themanipulator mount coordinate frame 341 represents a suitable model forrepresenting positions and/or orientations associated with amanipulator, such as manipulator 260. The manipulator mount coordinateframe 341 is associated with a manipulator mount, such as themanipulator mount 262 of the corresponding articulated arm. The armmounting platform to manipulator mount transform 344 is then based onone or more kinematic models of the links and joints of thecomputer-assisted device between the arm mounting platform and thecorresponding manipulator mount, such as the corresponding set-up joints240, along with past and/or current joint sensor readings of thecorresponding set-up joints 240.

The remote center of motion coordinate frame 342 is associated with aremote center of motion of the instrument mounted on the manipulator,such as the corresponding remote center of motion 274 of thecorresponding manipulator 260. The manipulator mount to remote center ofmotion transform 345 is then based on one or more kinematic models ofthe links and joints of the computer-assisted device between thecorresponding manipulator mount and the corresponding remote center ofmotion, such as the corresponding joints 264, corresponding links 266,and corresponding carriage 268 of the corresponding manipulator 260,along with past and/or current joint sensor readings of thecorresponding joints 264. When the corresponding remote center of motionis being maintained in fixed positional relationship to thecorresponding manipulator mounts, such as in the embodiments of FIG. 2,the manipulator mount to remote center of motion transform 345 includesan essentially static translational component that does not change asthe manipulator and instrument are operated and a dynamic rotationalcomponent that changes as the manipulator and instrument are operated.

The instrument coordinate frame 343 is associated with an end effectorlocated at the distal end of the instrument, such as the correspondingend effector 276. The remote center of motion to instrument transform346 is then based on one or more kinematic models of the links andjoints of the computer-assisted device that move and/or orient thecorresponding instrument, end effector, and remote center of motion,along with past and/or current joint sensor readings. In some examples,the remote center of motion to instrument transform 346 accounts for theorientation at which the shaft, such as the corresponding shaft 272,passes through the remote center of motion and the distance to which theshaft is advanced and/or withdrawn relative to the remote center ofmotion. In some examples, the remote center of motion to instrumenttransform 346 may be constrained to reflect that the insertion axis ofthe shaft of the instrument passes through the remote center of motionand accounts for rotations of the shaft and the end effector about theaxis defined by the shaft.

In the kinematic model 300, the kinematic relationships of a second oneof the articulated arms is captured using a manipulator mount coordinateframe 351, a remote center of motion coordinate frame 352, an instrumentcoordinate frame 353, an arm mounting platform to manipulator mounttransform 354, a manipulator mount to remote center of motion transform355, and a remote center of motion to instrument transform 356. Themanipulator mount coordinate frame 351 represents a suitable model forrepresenting positions and/or orientations associated with amanipulator, such as manipulator 260. The manipulator mount coordinateframe 351 is associated with a manipulator mount, such as themanipulator mount 262 of the corresponding articulated arm. The armmounting platform to manipulator mount transform 354 is then based onone or more kinematic models of the links and joints of thecomputer-assisted device between the arm mounting platform and thecorresponding manipulator mount, such as the corresponding set-up joints240, along with past and/or current joint sensor readings of thecorresponding set-up joints 240.

The remote center of motion coordinate frame 352 is associated with aremote center of motion of the manipulator mounted on the articulatedarm, such as the corresponding remote center of motion 274 of thecorresponding manipulator 260. The manipulator mount to remote center ofmotion transform 355 is then based on one or more kinematic models ofthe links and joints of the computer-assisted device between thecorresponding manipulator mount and the corresponding remote center ofmotion, such as the corresponding joints 264, corresponding links 266,and corresponding carriage 268 of the corresponding manipulator 260,along with past and/or current joint sensor readings of thecorresponding joints 264. When the corresponding remote center of motionis being maintained in fixed positional relationship to thecorresponding manipulator mounts, such as in the embodiments of FIG. 2,the mount to remote center of motion transform 355 includes anessentially static translational component that does not change as themanipulator and instrument are operated and a dynamic rotationalcomponent that changes as the manipulator and instrument are operated.

The instrument coordinate frame 353 is associated with an end effectorlocated at the distal end of the instrument, such as the correspondinginstrument 270 and/or end effector 276. The remote center of motion toinstrument transform 356 is then based on one or more kinematic modelsof the links and joints of the computer-assisted device that move and/ororient the corresponding instrument, end effector, and remote center ofmotion, along with past and/or current joint sensor readings. In someexamples, the remote center of motion to instrument transform 356accounts for the orientation at which the shaft, such as thecorresponding shaft 272, passes through the remote center of motion andthe distance to which the shaft is advanced and/or withdrawn relative tothe remote center of motion. In some examples, the remote center ofmotion to instrument transform 356 may be constrained to reflect thatthe insertion axis of the shaft of the instrument passes through theremote center of motion and accounts for rotations of the shaft and theend effector about the insertion axis defined by the shaft.

In the kinematic model 300, the kinematic relationships of a third oneof the articulated arms is captured using a manipulator mount coordinateframe 361, a remote center of motion coordinate frame 362, a cameracoordinate frame 363, an arm mounting platform to manipulator mounttransform 364, a manipulator mount to remote center of motion transform365, and a remote center of motion to camera transform 366. Themanipulator mount coordinate frame 361 represents a suitable model forrepresenting positions and/or orientations associated with amanipulator, such as manipulator 260. The manipulator mount coordinateframe 361 is associated with a manipulator mount, such as themanipulator mount 262 of the corresponding articulated arm. The armmounting platform to manipulator mount transform 364 is then based onone or more kinematic models of the links and joints of thecomputer-assisted device between the arm mounting platform and thecorresponding manipulator mount, such as the corresponding set-up joints240, along with past and/or current joint sensor readings of thecorresponding set-up joints 240.

The remote center of motion coordinate frame 362 is associated with aremote center of motion of the manipulator mounted on the articulatedarm, such as the corresponding remote center of motion 274 of thecorresponding manipulator 260. The manipulator mount to remote center ofmotion transform 365 is then based on one or more kinematic models ofthe links and joints of the computer-assisted device between thecorresponding manipulator mount and the corresponding remote center ofmotion, such as the corresponding joints 264, corresponding links 266,and corresponding carriage 268 of the corresponding manipulator 260,along with past and/or current joint sensor readings of thecorresponding joints 264. When the corresponding remote center of motionis being maintained in fixed positional relationship to thecorresponding manipulator mounts, such as in the embodiments of FIG. 2,the mount to remote center of motion transform 365 includes anessentially static translational component that does not change as themanipulator and instrument are operated and a dynamic rotationalcomponent that changes as the manipulator and instrument are operated.

The camera coordinate frame 363 is associated with an imaging device,such an endoscope, mounted on the articulated arm. The remote center ofmotion to camera transform 366 is then based on one or more kinematicmodels of the links and joints of the computer-assisted device that moveand/or orient the imaging device and the corresponding remote center ofmotion, along with past and/or current joint sensor readings. In someexamples, the remote center of motion to camera transform 366 accountsfor the orientation at which the shaft, such as the corresponding shaft272, passes through the remote center of motion and the distance towhich the shaft is advanced and/or withdrawn relative to the remotecenter of motion. In some examples, the remote center of motion tocamera transform 366 may be constrained to reflect that the insertionaxis of the shaft of the imaging device passes through the remote centerof motion and accounts for rotations of the imaging device about theaxis defined by the shaft.

As discussed above and further emphasized here, FIG. 3 is merely anexample which should not unduly limit the scope of the claims. One ofordinary skill in the art would recognize many variations, alternatives,and modifications. According to some embodiments, the registrationbetween the surgical table and the computer-assisted device may bedetermined between the table top coordinate frame 310 and the devicebase coordinate frame 320 using an alternative registration transform.When the alternative registration transform is used, registrationtransform 325 is determined by composing the alternative registrationtransform with the inverse/reverse of the table base to table toptransform 315. According to some embodiments, the coordinate framesand/or transforms used to model the computer-assisted device may bearranged differently dependent on the particular configuration of thelinks and joints of the computer-assisted device, its articulated arms,its end effectors, its manipulators, and/or its instruments. Accordingto some embodiments, the coordinate frames and transforms of thekinematic model 300 may be used to model coordinate frames andtransforms associated with one or more virtual instruments and/orvirtual cameras. In some examples, the virtual instruments and/orcameras may be associated with previously stored and/or latchedinstrument positions, projections of instruments and/or cameras due to amotion, reference points defined by a surgeon and/or other personnel,and/or the like.

As described previously, as a computer-assisted system, such ascomputer-assisted systems 100 and/or 200, is being operated it would bedesirable to allow continued control of the instrument and/or endeffectors while motion of a surgical table, such as surgical tables 170and/or 280, is allowed. In some examples, this may allow for a lesstime-consuming procedure as surgical table motion occurs without havingto remove instruments from body openings on the patient. In someexamples, this allows a surgeon and/or other medical personnel tomonitor organ movement while the surgical table motion is occurring toobtain a more optimal surgical table pose. In some examples, this alsopermits active continuation of a surgical procedure during surgicaltable motion. Some modes of operation allow motion of the articulatedstructure in the surgical table (i.e., table movement) while one or moreinstruments are inserted into body openings on the patient to thepatient. Examples of systems permitting active continuation of asurgical procedure during surgical table motion are shown in U.S.Provisional Patent Application No. 62/134,207 entitled “System andMethod for Integrated Surgical Table,” which was filed Mar. 17, 2015,and concurrently filed PCT Patent Application No. PCT/US2015/057656entitled “System and Method for Integrated Surgical Table” and publishedas WO2016/069648 A1, both of which are hereby incorporated by referencein their entirety. During the table movement, it is generally desired tohave the remote centers of motion or other control points, correspondingto body openings, body orifices, and/or locations where an instrument isinserted through an incision site on the patient, move with the patientto limit stresses on the anatomy of the patient at the incision pointsand/or to maintain instrument positioning. In some examples, this may beaccomplished using instrument dragging by releasing and/or unlocking oneor more joints of the articulated arm and allowing the body wall of thepatient at the body opening to drag the control points and theassociated instruments as the patient moves. However, an articulated armand/or end effector may occasionally encounter a disturbance thatresults in a loss of the ability to freely track the table movement sothat the control points do not remain coincident with the body openings.Examples of disturbances that may cause loss of tracking ability includereaching range of motion limits in the joints of the articulated arms,encountering an obstruction such as a tangled cable, loss of cannularetention (i.e., the cannula associated with a control point slippingout from the body wall at the body opening), movement of the patient onthe table, a brake release failure, a collision between two arms and/orbetween an arm and the patient body, and/or the like. Accordingly, insome examples, it may be desired to monitor the configuration of thecontrol points during table movement to ensure that their actualconfiguration at a given time is consistent with their expectedconfiguration based on the table motion. When a deviation between theactual and expected configurations of the control points is detected, acorresponding remedial action, such as disabling table movement, brakingthe articulated arms, alerting the user and/or the like, may be taken.Further, according to some embodiments, it may be desirable to detectand/or report offending arms (i.e., the one or more articulated arms wassubject to and/or was most impacted by the disturbance that caused thealert to be raised) to facilitate corrective action.

FIG. 4 is a simplified diagram of the method 400 of monitoring one ormore control points during table movement according to some embodiments.One or more of the processes 410-460 of method 400 may be implemented,at least in part, in the form of executable code stored onnon-transient, tangible, machine readable media that when run by one ormore processors (e.g., the processor 140 in control unit 130) may causethe one or more processors to perform one or more of the processes410-460. In some embodiments, method 400 may be used to detectdisturbances that prevent control points, such as those located at abody opening, body orifice, or incision site in patient from trackingtable movement as expected. In some examples consistent with theembodiments of FIG. 2, the one or more control points may be instancesof remote center of motion 274, and table movement may correspond tomotion of articulated structure 290 in the surgical table 280. One ofordinary skill would understand that method 400 may be adapted tomonitor the movement of remote centers of motion or any other controlpoints that are expected to predictably move as a result of the tablemovement.

According to some embodiments, method 400 supports one or more usefulimprovements over methods that do not monitor one or more control pointsduring table movement. In some examples, method 400 may reduce thelikelihood of injury to the patient or equipment during table movementby detecting a disturbance that prevents the control points from freelytracking the table movement and allowing a corresponding remedial actionto be taken, such as halting table movement and/or alerting an operatorof the disturbance. In some examples, method 400 may further facilitateoperator intervention by reporting one or more offending arms that weresubject to and/or were most impacted by the disturbance. In someexamples, method 400 may reduce the likelihood of raising false alarmsover other methods by monitoring a selected set of geometric attributesof the control point configuration and/or by setting thresholds thataccurately distinguish routine aberrations from unsafe disturbances.

At a process 410, a latched configuration of the control points isdetermined. The latched configuration specifies one or more attributesof the geometric arrangement of the control points (collectivelyreferred to as the control point constellation) in a reference frame. Insome embodiments, the geometric attributes may include the positions ofthe control points, the orientation of the control point constellation,the point-to-point distances between pairs of control points, theinterior angles formed between sets of three control points, the centerof curvature of the control point constellation, and/or the like. Insome examples, the latched configuration may be determined using sensorreadings and/or kinematic models, such as kinematic model 300, toascertain the position of each control point and/or to derivecorresponding geometric attributes of the control point constellation.The selection of the reference frame depends on an operating mode. Insome embodiments, the reference frame may be any coordinate frame thatis fixed relative to a world coordinate frame. In such examples,consistent with the embodiments of FIGS. 2 and 3, any of the device basecoordinate frame 320, arm mounting platform coordinate frame 330, and/ortable base coordinate frame 305 may be used as the reference frame. Afixed reference frame may be used in some operating modes for trackingthe positions of each control point individually. In some embodiments,the reference frame may be a dynamic coordinate frame where the positionof the origin and/or the orientation of the axes of the reference framedepend upon the current position and/or orientation of the controlpoints, table top, and/or other moving components of the system. Oneexample of a dynamic reference frame is a barycentric reference frame,where the origin of the reference frame is an average and/or weightedaverage position of the control points at a current time and theorientation of the reference frame is fixed relative to a worldcoordinate frame or a table top coordinate frame. A barycentricreference frame may optionally be used in some operating modes fortracking the movement of the control points relative to one another, inwhich case common-mode translational motion of the control points (i.e.translational motion that applies to all control points equally) isirrelevant. Once the process 410 is complete, table movement maycommence.

At a process 420, an expected configuration of the control points isdetermined based on the table movement. The expected configurationaccounts for predicted changes in the position and/or orientation of thecontrol points relative to the latched configuration determined duringprocess 410 based on table movement. In some embodiments, the expectedconfiguration may specify a set of geometric attributes corresponding tothose specified by the latched configuration. In some embodiments, theexpected configuration may instead and/or additionally specify one ormore differential attributes that are defined relative to the latchedconfiguration, such as a change in position, a change in orientation,and/or the like. In some examples, such as when using instrumentdragging, the control points are expected to the move with the table. Insuch embodiments, for example, when the height of the table changes by agiven distance, the vertical position of each of the control points in afixed reference frame is expected to change by the same distance.Similarly, when the table is rotated by a given angle, such as a tilt,Trendelenburg, and/or reverse Trendelenburg rotation, the orientation ofthe control point constellation in a barycentric reference frame isexpected to rotate by the same angle. According to some embodiments, oneor more geometric attributes of the control point constellation is notbe expected to change during table movement. For example, the interiorangles, point-to-point distances, the center of curvature of the controlpoint constellation, and/or the like is expected to remain constantduring table movement.

At a process 430, an actual configuration of the control points duringtable movement is determined. In some examples, the actual configurationmay be determined using position sensors and/or kinematic models toascertain the position of each control point and/or the correspondinggeometric attributes of the control point constellation in the referenceframe of the process 410. In some embodiments, the actual configurationspecifies a set of geometric attributes that correspond to thosespecified by the latched configuration of the process 410 and/or theexpected configuration determined by process 420.

At a process 440, the actual and expected configurations of the controlpoints are compared to determine if a difference between theconfigurations exceeds one or more predetermined thresholds. The typesand/or values of the predetermined thresholds depend upon the geometricattributes being compared. In some examples, when the geometricattributes include control point positions, the predetermined thresholdrepresents a maximum allowable distance between the actual and expectedpositions. Similarly, when the geometric attributes include theorientation of the control point constellation, the predeterminedthreshold represents a maximum allowable angle between the actual andexpected orientations. In some examples, when the geometric attributesinclude a position associated with the control point constellation, suchas the centroid position, the predetermined threshold represents amaximum allowable distance between the actual and expected position. Infurther examples, when the geometric attributes include the center ofcurvature of the control point constellation, the predeterminedthreshold represents a restriction that the center of curvature belocated below the centroid of the control point constellation. Variousother types and/or values of predetermined thresholds may optionally beapplied to other geometric attributes in a manner consistent with theunderlying characteristics of the attributes being compared.

In general, the values of the predetermined thresholds are selectedaccording to the desire to accurately detect unsafe disturbances to thecontrol point configuration while minimizing false alarms resulting fromroutine deviations between the actual and expected configurations (e.g.,small oscillations in the articulated arms, small lags due to instrumentdragging, allowable distortions in the body wall of the patient, and/orthe like). In some embodiments, the value of the one or more of thepredetermined thresholds is selected based on a clinically acceptabledistance that a control point can move relative to the patient's bodyduring table movement. In some embodiments, the clinically acceptabledistance is about 12 mm. Thus, in some embodiments, the process 440 mayinclude performing one or more computations to determine a value for apredetermined threshold that is consistent with the clinicallyacceptable distance being maintained. The computations depend on thecharacteristics of the geometric attributes being compared. For example,when the geometric attribute is an angle, the computation involvesconverting the clinically acceptable distance into an equivalent angularvalue in the reference frame.

Comparing the actual and expected configurations to determine if adifference between the configurations exceeds one or more predeterminedthresholds may be achieved in a variety of ways. Thus, the process 440as described above is merely an example and should not be undulylimiting. According to some examples, rather than converting aclinically acceptable distance into a predetermined threshold consistentwith a geometric attribute being compared, the geometric attribute beingcompared may instead be converted into a distance value consistent withthe clinically acceptable distance. According to some examples, ratherthan comparing the actual and expected configurations directly, a rangeof allowable values for the geometric attributes of the actualconfiguration may be determined based on the expected configuration andthe predetermined threshold. According to such examples, when thegeometric attribute of the actual configuration is not within the rangeof allowable values, the predetermined threshold is determined to beexceeded.

During the process 440, when it is determined that the one or morepredetermined thresholds have not been exceeded, then table movement isallowed to proceed and the method 400 returns to the process 420 tocontinue monitoring the control point configuration. However, when it isdetermined that one or more predetermined thresholds have been exceeded,then an alert is raised and the method 400 proceeds to a process 450described below.

At a process 450, one or more control points and corresponding arms thatcaused the alert to be raised at the process 440 (referred to asoffending arms) are determined. One or more techniques for determiningthe offending arms may be used. In some embodiments, when a jointreaches a range of motion limit, an articulated arm that corresponds tothe range of motion limit event may be identified as an offending arm.In some embodiments, an error value associated with each control pointis determined and the corresponding articulated arm with the greatesterror value (i.e., the worst offender arm) and/or the one or morecorresponding articulated arms with an error value that exceeds athreshold is identified as the one or more offending arms. In someembodiments, when the actual and expected configurations specify actualand expected positions for each control point, the error value includesthe distance between the actual and expected positions. In someembodiments, the error value includes the difference between an actualand expected path length, where the path length indicates an amount ofdistance that each control point has traveled during table motion. Toillustrate how the path length difference works, the following exampleis provided. An expected position travels to the right by 10 units andthen to left by 5 units, while an actual position travels to the rightby 7 units and to then to the left by 2 units. Both the actual andexpected positions end up 5 units to the right of the starting positionafter the movement, so the distance between the actual and expectedpositions is 0 units. However, the expected position traveled along apath with a length of 15 units while the actual position traveled a pathwith a length of 9 units, so the difference between the actual andexpected path length is 6 units. Thus, in some embodiments, the pathlength difference is used to capture certain deviations between theactual and expected positions that are obscured when using the finaldistance between the actual and expected positions as the error value.

At a process 460, one or more remedial actions are taken based on thealert raised at the process 440 and/or based on the offending armsdetermined at the process 450. In some embodiments, the remedial actionsincludes one or more of stopping and/or disabling table movement,alerting an operator to the disturbance, reporting the offending arms tothe operator, applying brakes to one or more of the articulated arms,applying compensation to one or more of the articulated arms, loggingand/or dispatching an error report, and/or the like. In someembodiments, table movement is stopped as soon as the alert is raisedand optionally remains disabled until the operator performs one or moreactions, such as manually repositioning the offending arms and/orperforming an inspection to identify and correct the disturbances. Insome embodiments, the operator may optionally be alerted to thedisturbance using an audio, visual, and/or haptic signaling mechanismsuch as an audio alarm, a flashing light (e.g. an LED), a message on adisplay screen, a vibration of a surgical table command unit, and/or thelike. Similarly, the offending arms may optionally be reported to theoperator using any appropriate signaling mechanism, such as the audio,visual, and/or haptic signaling mechanisms mentioned above. In someembodiments, brakes may be fully and/or partially applied to one or moreof the articulated arms, including the offending arms and/or all of thearticulated arms, to prevent and/or reduce further motion of the controlpoints relative to the table. In some embodiments, an error signal mayoptionally be sent to one or more joints of the articulated arms toattempt to compensate for the deviation of between the actual andexpected configuration by applying a counteracting force to the one ormore joints. In some embodiments, an error report, which includesdetails relevant to the alert being raised such as a timestamp, systemidentifier, operator identifier, offending arm identifiers, and/or thelike, may be logged and/or dispatched to a local and/or remote computerapplication for informational purposes and/or to allow additionalremedial actions to be taken.

As discussed above and further emphasized here, FIG. 4 is merely anexample which should not unduly limit the scope of the claims. One ofordinary skill in the art would recognize many variations, alternatives,and modifications. According to some embodiments, method 400 may omitone or more of processes 410-460. For example, some embodiments may omitthe process 450 of offending arm detection and alert the operator ofdisturbances without identifying offending arms. Some embodiments mayomit the process 420 of determining an expected configuration (stateddifferently, the expected configuration may be equivalent to the latchedconfiguration determined at the process 410), particularly when thegeometric attributes specified by the latched configuration are notexpected to change during table motion. Geometric attributes that arenot expected to change during table motion may include point-to-pointdistances between control points, interior angles formed by sets ofthree control points, the center of curvature of the control pointconstellation in a barycentric reference frame, and/or the like. Suchembodiments may be used, for example, when no information about thetable movement is available and/or when the table movement is performedwithout convert the table movement into the reference frame of thecontrol point constellation using a registration transform. According tosome embodiments, the sequence of the processes 410-460 performed duringmethod 400 may be rearranged and/or one or more of the processes 410-460may be performed concurrently. In some examples, the process 420 ofdetermining an expected configuration may be performed before,concurrently with, or after the process 430 of determining an actualconfiguration. In some examples, the process 450 of determining theoffending arms may be performed before, concurrently with, or after theprocess 460 of raising an alert. According to some examples, a pluralityof predetermined thresholds may be checked during the process 440 totrigger remedial actions of varying severity at the process 460. Forexample, a first predetermined threshold may, when exceeded, trigger awarning to the operator at the process 460 but allow continued tablemovement, and a second predetermined threshold may, when exceeded,disable table movement at the process 460.

FIG. 5 is a simplified diagram of a control point position 500 duringtable movement in a height-only mode according to some embodiments. FIG.5 depicts traces of vertical position (z axis) versus time (t axis). Insome embodiments consistent with the embodiments of FIG. 4, FIG. 5illustrates an application of the method 400 during table movement in aheight-only mode (i.e. where the table movement is restricted totranslation in a vertical direction). In some examples consistent withFIGS. 2 and 3, the height-only mode may be enforced when the number ofcontrol points being monitored is less than three and/or when theregistration between the surgical table and the computer-assisted devicehas not been performed and the table base to device base transform 325is not known.

Expected position 510 and actual position 520 are traces that depict anexpected position and actual position of a control point over time,respectively. Predetermined threshold 530 is a range of allowablepositions corresponding to expected position 510 over time. Phases 540include a pre-latching phase 540 a, a tracking phase 540 b, anundetected disturbance phase 540 c, and a detected disturbance phase 540d. During pre-latching phase 540 a, no table movement is permitted, asthe control point monitoring has not yet begun. Between pre-latchingphase 540 a and tracking phase 540 b, a latched position of the controlpoint is determined and height-only table movement is subsequentlypermitted. In embodiments consistent with FIG. 4, the latched positionis determined using the process 410 where the control pointconfiguration specifies the position of the control point in a fixedreference coordinate frame.

During tracking phase 540 b, height-only table movement occurs, and thecontrol point freely tracks the table movement. When the table is raisedas depicted in FIG. 5, the expected position 510 rises with the table.The actual position 520 generally tracks the expected position 510during tracking phase 540 b, although some small, routine deviationsbetween the actual and expected positions may be observed. Inembodiments consistent with FIG. 4, the expected position 510 isdetermined using the process 420 and the actual position 520 isdetermined using the process 430. The expected position 510 and actualposition 520 may be represented in the reference frame of the latchedposition and/or differentially represented relative to the latchedposition. Also during tracking phase 540 b, the expected position 510and actual position 520 are compared to determine whether the actualposition 520 is within the allowable range given by the predeterminedthreshold 530. In embodiments consistent with FIG. 4, the comparison isperformed using the process 440 where the value of the predeterminedthreshold is set to a clinically acceptable distance, such as 12 mm.Although only the vertical component of the allowable range of positionsis depicted in FIG. 5 for simplicity, it is to be understood that thecomparison may be performed in up to three dimensions, such that adeviation between the expected position 510 and actual position 520 inany direction may be detected. Thus, in some embodiments, the allowablerange of positions forms a sphere of allowable positions in threedimensions. As depicted in FIG. 5, during the tracking phase 540 b thedifference between the expected position 510 and actual position 520does not exceed the predetermined threshold 530.

Between tracking phase 540 b and undetected disturbance phase 540 c, adisturbance 550 occurs that prevents the control point from freelytracking the table movement. Disturbance 550 may include any of thedisturbances discussed above with respect to FIG. 4, such asencountering an obstacle that blocks the control point from risingbeyond a given height as depicted in FIG. 5. Thus, during undetecteddisturbance phase 540 c the actual position 520 no longer closely tracksthe expected position 510. However, the distance between the actualposition 520 and expected position 510 does not yet exceed thepredetermined threshold 530. Therefore, table movement is allowed tocontinue while the distance between the actual position 520 and expectedposition 510 approaches the predetermined threshold 530.

Between undetected disturbance phase 540 c and detected disturbancephase 540 d, the distance between the actual position 520 and expectedposition reaches the predetermined threshold 530, causing an alert to beraised. In embodiments consistent with FIG. 4, offending arm detectionusing the process 450 and/or remedial actions using the process 460 maysubsequently occur at the beginning of detected disturbance phase 540 d.In the embodiment depicted in FIG. 5, table movement is disabled duringdisturbance detected phase 540 d such that the difference between theactual position 520 and expected position 510 does not increase beyondthe predetermined threshold 530. Further, when more than one controlpoint is being monitored, the one or more offending arms may bedetermined using any of the mechanisms discussed previously with respectto the process 450, such as by identifying the control point with thelargest difference between actual and expected positions and/or byidentifying all of the control points for which the predeterminedthreshold 530 is exceeded. The operator may optionally be alerted to thedetected disturbance and/or the identity of the offending arms by any ofthe feedback mechanisms discussed with respect to the process 460, suchas an audible alarm indicating that a disturbance was detected and/orflashing lights that indicate the offending arms. In some embodiments,table movement may remain disabled until the operator addresses thedisturbance, such as by manually repositioning the one or more offendingarms.

As discussed above and further emphasized here, FIG. 5 is merely anexample which should not unduly limit the scope of the claims. One ofordinary skill in the art would recognize many variations, alternatives,and modifications. According to some embodiments, the z axis of FIG. 5may represent any geometric attribute of a control point constellation,including a vertical or horizontal position, an orientation, apoint-to-point distance, interior angle, and/or the like. Accordingly,procedure 500 may illustrate a method for monitoring any geometricattribute of the control point constellation.

FIG. 6 is a simplified diagram of a control point constellation 600during rotational table movement according to some embodiments. FIG. 6depicts a three-dimensional arrangement of a control point constellationin a barycentric reference frame with the origin located at the averageposition of the plurality of control points. In some embodimentsconsistent with the embodiments of FIG. 4, FIG. 6 illustrates anapplication of the method 400 to table movement in a mode whererotations such as tilt, Trendelenburg, and/or reverse Trendelenburgrotations are allowed. In some examples consistent with FIGS. 2 and 3,rotational table movement may be allowed when the registration transform325 is known, such as when the number of control points being monitoredis at least three and/or after a registration between the surgical tableand the computer-assisted device has been performed.

Expected configuration 610 includes paths 610 a-c that represent theexpected positions of control points in control point constellation 600over time, actual configuration 620 includes paths 620 a-c thatrepresent actual positions of the control points over time, andpredetermined threshold 630 includes ranges of allowable positions 630a-c corresponding to the expected configuration 610 over time. Referenceframe 640 represents a barycentric reference frame used to determine thecontrol point positions. Prior to rotating the table and/or prior todetermining a latched configuration of the control point constellation,a registration transform is determined. In some embodiments consistentwith FIGS. 2 and 3, the registration transform may correspond toregistration transform 325 and/or alternate registration transform 325and may be determined using a θz registration and/or an XY registration.Accordingly, a rotation of the table relative to table base coordinates305 by a given angle may be converted into device base coordinates 320by application of registration transform 325.

At the beginning of table motion, and after Oz and/or XY registration, alatched configuration of the control point constellation is determined.In some embodiments consistent with the embodiments of FIG. 4, thelatched configuration is determined using the process 410 in thereference frame 640 before table rotation. The latched configurationspecifies the position of each control point and/or one or moregeometric attributes of the control point constellation such as themagnitude of the angle formed by the control point constellationrelative to the reference frame 640 before table rotation. Once thelatched configuration is determined, control point monitoring duringtable movement begins. In some embodiments consistent with theembodiments of FIG. 4, control point monitoring is performed using theprocesses 420-440 to determine whether the actual configuration of thecontrol point constellation has deviated from the expected configurationof the control point constellation by more than the predeterminedthreshold 630. Because reference frame 640 is barycentric, translationalmovement of the table, such as a height adjustment, slide adjustment,and/or translational movement corresponding to a rotational movement ofthe table at positions other than an isocenter, does not change theexpected configuration 610. Meanwhile, rotational movement of the tablechanges the orientation of the expected configuration 610, with thedirection and magnitude of the change being determined using thedetected table movement and the registration transform. It should benoted that although the actual center of the control point constellationmay be translating, because the coordinate frames 640 are barycentric itis only the relative positions about the center of the control pointconstellation that are considered.

Control point constellation 600 illustrates a rotation that results in achange in the orientation of expected configuration relative to thereference frame 640. Like the example shown in FIG. 5, the actualconfiguration 620 generally tracks the expected configuration 610 withinthe predetermined threshold 630. For simplicity, the geometric attributedepicted in FIG. 6 is position, but it is to be understood that othergeometric attributes, such as the magnitude of the angle formed by theactual configuration 620 relative to reference frame 640, may also becompared with expected configuration 610 and checked against acorresponding threshold value (i.e., a rotation magnitude check).

Control point constellation 600 also illustrates a disturbance 650 thatresults in control point path 620 c diverging from the expected path 610c beyond the allowable range 630 c. In some embodiments consistent withthe embodiments of FIG. 4, surpassing the threshold results in an alertbeing raised during the process 440 such that one or more of theprocesses of offending arm identification 450 and/or remedial action 460are performed. In some embodiments, the offending arm corresponding tocontrol point path 620 c may be determined using any of the mechanismsdiscussed previously with respect to the process 450, such as byidentifying the control point with the largest difference between theactual and expected path lengths. In some embodiments, such as whenperforming a rotation magnitude check, all of the arms may be identifiedas offending arms. The operator may be alerted to the detecteddisturbance and/or the identity of the offending arms by any of thefeedback mechanisms discussed with respect to the process 460, such asan audible alarm indicating that a disturbance was detected and/orflashing lights that indicate the offending arm.

As discussed above and further emphasized here, FIG. 6 is merely anexample which should not unduly limit the scope of the claims. One ofordinary skill in the art would recognize many variations, alternatives,and modifications. According to some embodiments, control pointconstellation 600 may include more or less than the three control pointsdepicted. According to some embodiments, the control points may beapproximately collinear (i.e. forming a nearly straight line rather thana triangle and/or the like) in which case the sensitivity to rotationalmovement along one or more axes may decrease. In such embodiments, oneor more compensatory actions may be taken when a low sensitivityarrangement is identified, such as disabling rotational table movement,reducing the predetermined thresholds, alerting the operator to thereduced sensitivity and/or increased uncertainty of the monitoring,and/or the like.

Some examples of control units, such as control unit 130 may includenon-transient, tangible, machine readable media that include executablecode that when run by one or more processors (e.g., processor 140) maycause the one or more processors to perform the processes of method 400.Some common forms of machine readable media that may include theprocesses of method 400 are, for example, floppy disk, flexible disk,hard disk, magnetic tape, any other magnetic medium, CD-ROM, any otheroptical medium, punch cards, paper tape, any other physical medium withpatterns of holes, RAM, PROM, EPROM, FLASH-EPROM, any other memory chipor cartridge, and/or any other medium from which a processor or computeris adapted to read.

Although illustrative embodiments have been shown and described, a widerange of modification, change and substitution is contemplated in theforegoing disclosure and in some instances, some features of theembodiments may be employed without a corresponding use of otherfeatures. One of ordinary skill in the art would recognize manyvariations, alternatives, and modifications. Thus, the scope of theinvention should be limited only by the following claims, and it isappropriate that the claims be construed broadly and in a mannerconsistent with the scope of the embodiments disclosed herein.

What is claimed is:
 1. A computer-assisted device comprising: one ormore articulated arms; and a control unit coupled to the one or morearticulated arms; wherein the control unit is configured to performoperations comprising: determining, before movement of a table separatefrom the computer-assisted device, a latched spatial configuration of aplurality of control points associated with the one or more articulatedarms; determining one or more geometric attributes of the latchedspatial configuration; determining an actual spatial configuration ofthe plurality of control points as the one or more articulated armstrack the movement of the table; determining a difference between theone or more geometric attributes of the latched spatial configurationand corresponding one or more geometric attributes of the actual spatialconfiguration; and performing, based on the determined difference, aremedial action.
 2. The computer-assisted device of claim 1, wherein theremedial action comprises at least one action selected from a groupconsisting of: disabling movement of the table, alerting an operator,reporting an offending articulated arm, applying compensation to one ormore of the one or more articulated arms, and logging an error.
 3. Thecomputer-assisted device of claim 1, wherein the one or more geometricattributes comprise: a distance between two of the plurality of controlpoints; or an interior angle formed by three of the plurality of controlpoints; or a relative position of one of the plurality of control pointsabout a center, the center being of a control point constellation formedfrom the plurality of control points.
 4. The computer-assisted device ofclaim 1, wherein the one or more geometric attributes comprise amagnitude of an angle between the latched spatial configuration and areference frame.
 5. The computer-assisted device of claim 4, wherein thereference frame is: a barycentric reference frame; or a world coordinateframe; or a table top coordinate frame of the table.
 6. Thecomputer-assisted device of claim 4, wherein the reference frame isdetermined based on an operating mode of the computer-assisted device.7. The computer-assisted device of claim 1, wherein the movement of thetable comprises: a translational movement corresponding to rotationalmovement of the table, a height adjustment, or a slide adjustment. 8.The computer-assisted device of claim 1, wherein the one or morearticulated arms track the movement of the table using instrumentdragging.
 9. The computer-assisted device of claim 1, wherein a controlpoint of the plurality of control points corresponds to: a remote centerof motion of one of the one or more articulated arms; or a body opening,a body orifice, an incision site, or a location where an instrumentsupported by the computer-assisted device is inserted into a workspace.10. The computer-assisted device of claim 1, wherein the control unitfurther: determines an error value associated with each control point ofthe plurality of control points, and identifies an articulated arm ofthe one or more articulated arms with a greatest error value or with anerror value that exceeds a threshold value, as an offending arm.
 11. Amethod comprising: determining, by a control unit of a computer-assisteddevice, a latched spatial configuration of a plurality of control pointsbefore movement of a separate table, the plurality of control pointsassociated with a plurality of articulated arms of the computer-assisteddevice; determining, by the control unit, one or more geometricattributes of the latched spatial configuration; determining, by thecontrol unit, an actual spatial configuration of the plurality ofcontrol points during the movement of the table; determining, by thecontrol unit, a difference between the one or more geometric attributesof the latched spatial configuration and corresponding one or moregeometric attributes of the actual spatial configuration; andperforming, by the control unit based on the determined difference, aremedial action.
 12. The method of claim 11, wherein performing theremedial action comprises at least one action selected from a groupconsisting of: disabling movement of the table, alerting an operator,reporting an offending articulated arm, applying compensation to one ormore articulated arms of the computer-assisted device, and logging anerror.
 13. The method of claim 11, wherein the one or more geometricattributes comprise: a distance between two of the plurality of controlpoints; or an interior angle formed by three of the plurality of controlpoints; or a relative position of one of the plurality of control pointsabout a center, the center being of a control point constellation formedfrom the plurality of control points.
 14. The method of claim 11,wherein: the one or more geometric attributes comprise a magnitude of anangle between the latched spatial configuration and a reference frame;and the reference frame is: a barycentric reference frame; or a worldcoordinate frame; or a table top coordinate frame of the table.
 15. Themethod of claim 11, wherein: the one or more geometric attributescomprise a magnitude of an angle between the latched spatialconfiguration and a reference frame; and the reference frame isdetermined based on an operating mode of the computer-assisted device.16. The method of claim 11, further comprising: determining an errorvalue associated with each control point of the plurality of controlpoints, and identifying an articulated arm of the computer-assisteddevice with a greatest error value or with an error value that exceeds athreshold value, as an offending arm.
 17. A non-transitorymachine-readable medium comprising a plurality of machine-readableinstructions which when executed by one or more processors associatedwith a computer-assisted device are adapted to cause the one or moreprocessors to perform a method comprising: determining a latched spatialconfiguration of a plurality of control points before movement of aseparate table, the plurality of control points associated with aplurality of articulated arms of the computer-assisted device;determining one or more geometric attributes of the latched spatialconfiguration; determining an actual spatial configuration of theplurality of control points during the movement of the table;determining a difference between the one or more geometric attributes ofthe latched spatial configuration and corresponding one or moregeometric attributes of the actual spatial configuration; andperforming, based on the determined difference, a remedial action. 18.The non-transitory machine-readable medium of claim 17, whereinperforming the remedial action comprises at least one action selectedfrom a group consisting of: disabling movement of the table, alerting anoperator, reporting an offending articulated arm, applying compensationto one or more articulated arms of the computer-assisted device, andlogging an error.
 19. The non-transitory machine-readable medium ofclaim 17, wherein the one or more geometric attributes comprise: adistance between two of the plurality of control points; or an interiorangle formed by three of the plurality of control points; or a relativeposition of one of the plurality of control points about a center, thecenter being of a control point constellation formed from the pluralityof control points; or a magnitude of an angle between the latchedspatial configuration and a reference frame.
 20. The non-transitorymachine-readable medium of claim 17, further comprising: determining anerror value associated with each control point of the plurality ofcontrol points, and identifying an articulated arm of thecomputer-assisted device with a greatest error value or with an errorvalue that exceeds a threshold value, as an offending arm.